Pitivi fails in Ubuntu 16.04 because no python3/gst-python

[Masi]

Pitivi wants python3 based gst-python. Do `sudo apt-get install pitivi`. Do `pitivi`

        Missing soft dependency:
        - pycanberra not found on the system
            -> enables sound notifications when rendering is complete
        Missing soft dependency:
        - GnomeDesktop not found on the system
            -> file thumbnails provided by GNOME's thumbnailers
        Missing soft dependency:
        - Notify not found on the system
            -> enables visual notifications when rendering is complete

Complications.
- pitivi in Kazam's editing software list. Selecting it shows no warnings/output http://askubuntu.com/q/770165/25388.

Proposal 1: add warning when installing `pitivi` in apt-get.
Proposal 2: make python3 environment in the system which pitivi can use.

Ubuntu: 16.04 64 bit
Python: 2.7.11+
Related threads: https://bbs.archlinux.org/viewtopic.php?id=189438, http://ubuntuforums.org/showthread.php?t=2227629
Bug active: at least since 2014

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: pitivi 0.95-1
Uname: Linux 4.6.0-040600-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CurrentDesktop: Unity
Date: Sun Jun 19 12:33:54 2016
InstallationDate: Installed on 2016-06-05 (13 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
SourcePackage: pitivi
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.